In the discussion of the background that follows, reference is made to certain structures and/or methods. However, the following references should not be construed as an admission that these structures and/or methods constitute prior art. Applicant expressly reserves the right to demonstrate that such structures and/or methods do not qualify as prior art.
Conventional stump grinders are disclosed in U.S. Pat. Nos. 6,382,277 and 6,546,977, for example. Typically, the stump grinder includes a rotatable wheel or disk having a plurality of carbide-tipped teeth, including side cutting teeth projecting from the side surfaces of the disk and peripheral cutting teeth spaced about a circumferential outer surface of the disk. Each tooth includes a carbide cutting tip cemented or brazed to the a tooth body. A conventional cutting tip as used on each tooth includes a long flat cutting edge at the junction of its front and top faces. The tooth body includes a steel shaft for mounting the cutting tip to the disk, and the teeth are mounted so as to be inclined at various angles relative to the disk. In use, the disk is positioned in a generally vertical plane and rotationally driven about its centrally disposed horizontal axis, whereupon the cutting tips of the teeth contact and gradually disintegrate a stump.
As the stump grinding machine is operated, the carbide-tipped teeth cut through the wood fibers of tree stumps in the ground that are to be removed. The cutting action of the teeth through the earth and wood causes a great deal of wear on the tooth body, holders and steel disk. Often, long strings of chips are produced which makes cleanup afterward more difficult. When the conventional teeth are fastened to the sides of the cutter disk, the long flat top edge of the cemented carbide cutting tip must penetrate the hard stump. While the edge of the cutting tip remains sharp, this works well, but as the cutting edge becomes dull, the tip starts to “pound” the stump, tearing the wood apart in larger pieces. A dull cutting edge also requires increased horsepower and torque to drive the disk. Additionally, a blunt carbide cutting tip slows the cutting action and causes severe vibration throughout the grinding machine.
An exemplary stump grinding machine, the DURA Disk Cutting System utilizes flat radial cemented carbide-tipped teeth in which the cutting tips have a flat top, mounted on the edge of a steel disk using steel holders called pockets. The teeth lean alternately left and right of center on the disk, which allows the corners of the cemented carbide cutting tip, which are slightly rounded, to do the major portion of the cutting. However, since the face of the cutting tip is flat, the earth and wood cuttings travel down the face of the cutting tip and tooth to wear and erode the pockets and the disk.